During the installation of drywall, it is the practice to finish outside corners by affixing a metal angle piece along the corner from ceiling to floor. The angle piece covers and protects the edges of the drywall panels which are relatively brittle and subject to wear and damage by impact. The angle piece has a pair of elongate, thin gauge flanges which are joined lengthwise to form a bead at the vertex of the angle piece to provide increased stiffness.
Once affixed in place, drywall compound is applied to feather the surface of the drywall panels at the corner, thereby presenting a neat appearance. It is preferred to affix the angle piece to the drywall by crimping the flanges into the drywall at a number of points along the length of the corner. Crimping is efficient as it avoids the need for fasteners. However, it is generally performed manually using a crimping tool and a hammer. In attaching the angle piece to the drywall, the crimping tool is held in contact with the angle piece which is positioned against the drywall with the flanges engaging the panels at the outside corner. The crimping tool has a pair of jaws which are arranged so that each one faces one of the flanges of the angle piece. Each jaw is pivotally mounted on the tool and has a tooth which will move into the flange and crimp it to the drywall when the jaw is pivoted. An impact head is mounted on the tool between the jaws. The impact head moves relatively to the tool when struck with the hammer. The jaws are mechanically linked to the head and will pivot in response to the head motion. Crimping of the angle to the drywall is effected when the hammer strikes the impact head, causing the jaws to pivot and forcing the teeth into the flanges and the drywall.
Both the crimping tool and the hammer are heavy, and as multiple crimps must be made for each corner angle, it is apparent that such work will be fatiguing and may also result in repetitive motion injury. It is clear that efficiency and productivity would be improved and repetitive motion injury could be avoided by providing a power tool for crimping angle pieces to outside corners formed by drywall panels.